FDA staff cite safety issues with osteoporosis drug

WASHINGTON (Reuters) - Serious infections and cancer cases must be considered as U.S. advisers weigh the future of Amgen's most important experimental drug, regulatory reviewers said in documents released on Tuesday.

Amgen is seeking Food and Drug Administration approval to sell denosumab, a potential blockbuster, under the brand name Prolia. The company has applied to market the drug for treating and preventing osteoporosis in women past menopause, and treating and preventing bone loss from hormone therapy for breast or prostate cancer.

"Of particular concern, in light of these safety issues, is whether the risk/benefit balance for the osteoporosis prevention indication, both for patients with and without cancer, supports approval," FDA reviewers said in a memo prepared for an advisory panel review on Thursday.

Amgen shares rose 2 percent to $62.50 on Nasdaq.

BMO Markets analyst Jason Zhang said the safety issues were known to investors and "not surprising." He also said there had been concerns the FDA would order a strict risk-management plan for denosumab. The agency summary said reviewers would ask the advisory committee if a risk-management plan should be required if the drug wins approval.

The FDA will consider the panel recommendations before deciding whether to approve denosumab.